1. Field of the Invention
The present invention relates to a molded package comprising a metal member such as a lead electrode which supplies electric power to a semiconductor element incorporated into the mold member by way of insert molding, and further to a semiconductor device using the molded package as a support member.
2. Discussion of the Related Art
Conventionally, there has been a semiconductor device in which a light emitting semiconductor element, a protective element which protects the light emitting semiconductor element from a damage caused by overvoltage, and a plurality of semiconductor elements are housed in a recess of a molded package. In such a semiconductor device, a semiconductor element and a conductive wire which supplies electric power to the semiconductor element are connected to the surface of a metal member such as a lead electrode exposed in the recess of the molded package by way of die bonding or wire bonding. Further, the recess is encapsulated with a resin so as to cover the semiconductor element and the conductive wires, for the purpose of protecting them from the external environment. (For instance, see Japanese Patent Publication No. 2000-188425)
However, the thermal expansion coefficients of the metal member exposed in the recess of the molded package and the resin which encloses the recess are different, and so problems such as cracking at their interface occur. Such cracking may result in the resin falling out of from the molded package. Also, a gap created by the cracking adversely affects the optical properties of the light emitting device. Further, when the thermal stress exerted from the resin concentrates on the bonding portion of the conductive wires, the portion may detach from the surface of the lead electrode. This causes disconnection of the semiconductor element from the external electrode. Such problems become more significant when the number of semiconductor elements housed in the molded package increases. This is because a larger die bonding area is required for the corresponding lead electrodes and the number of wire bonds increase.
Therefore, an object of the present invention is to solve the problems described above and provide a semiconductor device having a high reliability.